The front-runners for Time’s “Person of the Year” award appear to be Federal Reserve Chairman Ben Bernanke — and Twitter. At Thursday’s annual debate leading up to the announcement, panelist and 2001 winner Rudy Giuliani nominated Bernanke, and also said he’d start using Twitter, even though he doesn’t even use e- mail. “Top Chef” judge Tom Colicchio also went with Ber nanke, though Gayle King and Barbara Walters both opted for the micro-blogging service. The choice of Pittsburgh Mayor Luke Ravensthal, on the other hand, was more political: the unemployed worker.